Collateral and Rationing Sorting Equilibria in Monopolistic and Competitive Markets
垄断势力及其福利损失测度：一个综述
垄断势力及其福利损失测度：一个综述胡德宝;陈甬军【摘要】垄断伴随着市场势力，将导致社会福利的损失，垄断势力的福利效应是一个重要的研究内容。
垄断势力最早由经济学家勒纳于1934年提出，1954年哈伯格沿着勒纳的研究思路，对美国垄断势力造成的福利损失进行了测度。
其后很多经济学家对其研究结论展开争论，出现了大量的理论和实证研究文献。
通过梳理垄断的福利损失测度的相关模型，如马歇尔剩余与希克斯剩余、塔洛克-波斯纳方法、莱宾斯坦-科马诺方法、迪克西特-斯特恩方法等，总结了研究的最新进展，分析表明这一研究对于在我国执行反垄断政策时把握反垄断的力度很有指导意义。
%Monopoly and the induced market power will cause social welfare losses ,and the study on effect on monopoly power is an importantpart .Market power was proposed by Lerner in 1934 as a pioneeringpaper ,and Harberger estimated the welfare loss of monopoly in America following the track of Lerner . His research conclusion raised arguments , and many economists had lots of theoretical and empirical papers on this subject .This paper sorts out related models that measure welfare loss caused by monopoly , such as Marshall surplus VS Hicks surplus , Tullock-Posner Approach , Leibenstein-Comanor Approach and Dixit-Stern Approach . Based on these , we summarize the latest research ,and cometo the conclusion w hich reveals that the study is significant in implementing the antitrust policy .【期刊名称】《山东大学学报（哲学社会科学版）》【年(卷),期】2014(000)001【总页数】11页(P41-51)【关键词】垄断势力;福利损失;需求弹性;测度【作者】胡德宝;陈甬军【作者单位】中国人民大学国际学院北京 100872;中国人民大学国际学院北京100872【正文语种】中文垄断是市场经济发展到一定阶段的产物，过度垄断将造成社会福利的损失基本上成为经济学界的共识。
经济学第七章--垄断竞争与寡头垄断市场
600亿美元
朗
600亿美元
500亿美元
低产量
300亿美元
500亿美元
若你是其中一国的总统，你的推理过程是……
上策均衡和纳什均衡
• 纳什均衡 乙
甲
表7－2 纳什均衡
上策均衡和纳什均衡
• 上策均衡－卡特尔困境 乙
甲
表7－3 卡特尔的困境
静态博弈和动态博弈
• 静态博弈与动态博弈
静态博弈指局中人同时决策或虽非同时决策， 但后决策者不知道先决策者采取什么策略的博 弈。
L)
=
1 3
B
(
1 22
1 24
1 26
L)
=
1 3
双头古诺模型的推广
设行业中有 m 个寡头厂商，则可以得到一般的结论：
每个寡头的供给量 = 市场总容量 1 m 1
整个行业的总供给量 = 市场总容量 m m 1
例题：
例：四个寡头的古诺模型，市场需求曲线为： P=100-Q
A 每个厂商生产25单位产品 B 市场价格为20 C 行业供给量为60单位 D 不存在稳定均衡
经济学第七章--垄断竞争 与寡头垄断市场
2021年7月23日星期五
第七章 垄断竞争市场与寡头垄断市场中价 格和产量的决定
垄断竞争与寡头是介于完全竞争与完 全垄断两个极端之间的兼具垄断与竞 争因素的市场类型，本章分析了垄断 竞争与寡头的定价策略与厂商行为， 介绍了说明市场均衡的经典模型，包 括古诺模型、伯特兰模型、斯威齐模 型。最后还介绍了博奕论的初步知识 。
• 纳什均衡 指参与博弈的每一局中人在给定其他局中人 策略的条件下选择上策所构成的一种策略组 合。
上策均衡和纳什均衡
囚徒困境（博弈论初步）
经济学术语重点
经济学术语National Income （国民收入）Aggregate Supply & Demand （总供应与总需求）Distribution & Re-distribution （分配与再分配）Unemployment & Inflation （失业与通货膨胀）Financial System （金融系统）Development & Growth （发展与增长）Sustainability （可持续性）Scarcity (稀缺性）Efficiency （效率）Supply and Demand （供应与需求）Elasticity （弹性）Equilibrium （均衡）Cost and Profit （成本与利润）Competition （竞争）Market （市场）（由于时间关系，术语数量很少，我会在以后的时间里不断的添加内容的。
）Factor要素factor demand要素需求factor market要素市场factors of production生产要素factor substitution要素替代factor supply要素供给fallacy of composition合成谬误final goods最终产品firm企业firms’ demand curve for labor企业劳动需求曲线firm supply curve企业供给曲线first-degree price discrimination第一级价格歧视first—order condition一阶条件fixed costs固定成本fixed input固定投入fixed proportions production function固定比例的生产函数flow流量fluctuation波动for whom to produce为谁生产free entry自由进入free goods自由品，免费品free mobility of resources资源自由流动free rider搭便车，免费搭车function函数future value未来值Ggame theory对策论、博弈论general equilibrium总体均衡general goods一般商品Giffen goods吉芬晶收入补偿需求曲线Giffen's Paradox吉芬之谜Gini coefficient吉尼系数golden rule黄金规则goods货物government failure政府失败government regulation政府调控grand utility possibility curve总效用可能曲线grand utility possibility frontier总效用可能前沿Hheterogeneous product异质产品Hicks—kaldor welfare criterion希克斯一卡尔多福利标准homogeneity齐次性homogeneous demand function齐次需求函数homogeneous product同质产品homogeneous production function齐次生产函数horizontal summation水平和household家庭how to produce如何生产human capital人力资本hypothesis假说Iidentity恒等式imperfect competition不完全竞争implicit cost隐性成本income收入Income compensated demand curveincome constraint收入约束income consumption curve收入消费曲线income distribution收入分配income effect收入效应income elasticity of demand需求收入弹性increasing cost industry成本递增产业increasing returns to scale规模报酬递增inefficiency缺乏效率index number指数indifference无差异indifference curve无差异曲线indifference map无差异族indifference relation无差异关系indifference set无差异集indirect approach间接法individual analysis个量分析individual demand curve个人需求曲线individual demand function个人需求函数induced variable引致变量induction归纳法industry产业industry equilibrium产业均衡industry supply curve产业供给曲线inelastic缺乏弹性的inferior goods劣品inflection point拐点information信息information cost信息成本initial condition初始条件initial endowment初始禀赋innovation创新input投入input—output投入—产出institution制度institutional economics制度经济学insurance保险intercept截距interest利息interest rate利息率intermediate goods中间产品internalization of externalities外部性内部化invention发明inverse demand function逆需求函数investment投资invisible hand看不见的手isocost line等成本线，isoprofit curve等利润曲线isoquant curve等产量曲线isoquant map等产量族Kkindled—demand curve弯折的需求曲线Llabor劳动labor demand劳动需求labour supply劳动供给labour theory of value劳动价值论labour unions工会laissez faire自由放任Lagrangian function拉格朗日函数Lagrangian multiplier拉格朗乘数，land土地law法则law of demand and supply供需法law of diminishing marginal utility边际效用递减法则law of diminishing marginal rate of substitution边际替代率递减法则law of diminishing marginal rate of technical substitution边际技术替代率law of increasing cost成本递增法则law of one price单一价格法则leader—follower model领导者--跟随者模型least—cost combination of inputs最低成本的投入组合leisure闲暇Leontief production function列昂节夫生产函数licenses许可证linear demand function线性需求函数linear homogeneity线性齐次性linear homogeneous production function线性齐次生产函数long run长期long run average cost长期平均成本long run equilibrium长期均衡long run industry supply curve长期产业供给曲线long run marginal cost长期边际成本long run total cost长期总成本Lorenz curve洛伦兹曲线loss minimization损失极小化1ump sum tax一次性征税luxury奢侈品Mmacroeconomics宏观经济学marginal边际的marginal benefit边际收益marginal cost边际成本marginal cost pricing边际成本定价marginal cost of factor边际要素成本marginal period市场期marginal physical productivity实际实物生产率marginal product边际产量marginal product of capital资本的边际产量marginal product of 1abour劳动的边际产量marginal productivity边际生产率marginal rate of substitution边替代率marginal rate of transformation边际转换率marginal returns边际回报marginal revenue边际收益marginal revenue product边际收益产品marginal revolution边际革命marginal social benefit社会边际收益marginal social cost社会边际成本marginal utility边际效用marginal value products边际价值产品market市场market clearance市场结清，市场洗清market demand市场需求market economy市场经济market equilibrium市场均衡market failure市场失败market mechanism市场机制market structure市场结构market separation市场分割market regulation市场调节market share市场份额markup pricing加减定价法Marshallian demand function马歇尔需求函数maximization极大化microeconomics微观经济学minimum wage最低工资misallocation of resources资源误置mixed economy混合经济model模型money货币monopolistic competition垄断竞争monopolistic exploitation垄断剥削monopoly垄断，卖方垄断monopoly equilibrium垄断均衡monopoly pricing垄断定价monopoly regulation垄断调控monopoly rents垄断租金monopsony买方垄断NNash equilibrium纳什均衡Natural monopoly自然垄断Natural resources自然资源Necessary condition必要条件necessities必需品net demand净需求no convex preference非凸性偏好no convexity非凸性no exclusion非排斥性nonlinear pricing非线性定价no rivalry非对抗性nonprice competition非价格竞争nonsatiation非饱和性non--zero—sum game非零和对策normal goods正常品normal profit正常利润normative economics规范经济学Oobjective function目标函数oligopoly寡头垄断oligopoly market寡头市场oligopoly model寡头模型opportunity cost机会成本optimal choice最佳选择optimal consumption bundle消费束perfect elasticity完全有弹性optimal resource allocation最佳资源配置optimal scale最佳规模optimal solution最优解optimization优化ordering of optimization(social) preference (社会)偏好排序ordinal utility序数效用ordinary goods一般品output产量、产出output elasticity产出弹性output maximization产出极大化Pparameter参数Pareto criterion帕累托标准Pareto efficiency帕累托效率Pareto improvement帕累托改进Pareto optimality帕累托优化Pareto set帕累托集partial derivative偏导数partial equilibrium局部均衡patent专利pay off matrix收益矩阵、支付矩阵perceived demand curve感觉到的需求曲线perfect competition完全竞争perfect complement完全互补品perfect monopoly完全垄断perfect price discrimination完全价格歧视perfect substitution完全替代品perfect inelasticity完全无弹性perfectly elastic完全有弹性perfectly inelastic完全无弹性plant size工厂规模point elasticity点弹性positive economics实证经济学post Hoc Fallacy后此谬误prediction预测preference偏好preference relation偏好关系present value现值price价格price adjustment model价格调整模型price ceiling最高限价price consumption curve价格费曲线price control价格管制price difference价格差别price discrimination价格歧视price elasticity of demand需求价格弹性price elasticity of supply供给价格弹性price floor最低限价price maker价格制定者price rigidity价格刚性price seeker价格搜求者price taker价格接受者price tax从价税private benefit私人收益principal—agent issues委托--代理问题private cost私人成本private goods私人用品private property私人财产producer equilibrium生产者均衡producer theory生产者理论product产品product transformation curve产品转换曲线product differentiation产品差异product group产品集团production生产production contract curve生产契约曲线production efficiency生产效率production function生产函数production possibility curve生产可能性曲线productivity生产率productivity of capital资本生产率productivity of labor劳动生产率profit利润profit function利润函数profit maximization利润极大化property rights产权property rights economics产权经济学proposition定理proportional demand curve成比例的需求曲线public benefits公共收益public choice公共选择public goods公共商品pure competition纯粹竞争rivalry对抗性、竞争pure exchange纯交换pure monopoly纯粹垄断Qquantity—adjustment model数量调整模型quantity tax从量税quasi—rent准租金Rrate of product transformation产品转换率rationality理性reaction function反应函数regulation调节，调控relative price相对价格rent租金rent control规模报酬rent seeking寻租rent seeking economics寻租经济学resource资源resource allocation资源配置returns报酬、回报returns to scale规模报酬revealed preference显示性偏好revenue收益revenue curve收益曲线revenue function收益函数revenue maximization收益极大化ridge line脊线risk风险Ssatiation饱和，满足saving储蓄scarcity稀缺性law of scarcity稀缺法则second—degree price discrimination二级价格歧视second derivative --阶导数second—order condition二阶条件service劳务set集shadow prices影子价格short—run短期short—run cost curve短期成本曲线short—run equilibrium短期均衡short—run supply curve短期供给曲线shut down decision关闭决策shortage短缺shut down point关闭点single price monopoly单一定价垄断slope斜率social benefit社会收益social cost社会成本social indifference curve社会无差异曲线social preference 社会偏好social security社会保障social welfare function社会福利函数socialism社会主义solution解space空间stability稳定性stable equilibrium稳定的均衡Stackelberg model斯塔克尔贝格模型static analysis静态分析stock存量stock market股票市场strategy策略subsidy津贴substitutes替代品substitution effect替代效应substitution parameter替代参数sufficient condition充分条件supply供给supply curve供给曲线supply function供给函数supply schedule供给表Sweezy model斯威齐模型symmetry对称性symmetry of information信息对称Ttangency相切taste兴致technical efficiency技术效率technological constraints技术约束technological progress技术进步technology技术third—degree price discrimination第三级价格歧视total cost总成本total effect总效应total expenditure总支出total fixed cost总固定成本total product总产量total revenue总收益total utility总效用total variable cost总可变成本traditional economy传统经济transitivity传递性transaction cost交易费用Uuncertainty不确定性uniqueness唯一性unit elasticity单位弹性unstable equilibrium不稳定均衡utility效用utility function效用函数utility index效用指数utility maximization效用极大化utility possibility curve效用可能性曲线utility possibility frontier效用可能性前沿VValue价值value judge价值判断value of marginal product边际产量价值variable cost可变成本variable input可变投入variables变量vector向量visible hand看得见的手vulgur economics庸俗经济学Wwage工资wage rate工资率Walras general equilibrium瓦尔拉斯总体均衡Walras's law瓦尔拉斯法则Wants需要Welfare criterion福利标准Welfare economics福利经学Welfare loss triangle福利损失三角形welfare maximization福利极大化Zzero cost零成本zero elasticity零弹性zero homogeneity零阶齐次性zero economic profit零利润Incidence（or tax incidence）归宿，或税赋归宿一项税收最终的经济负担者（相应于法定纳税人）。
Cournot与Stackelberg模型分析及比较
大化，将需求函数带入，得：
(100－Q1－Q2)Q2－10Q2=90Q2－Q1Q2－Q22
对 Q2 求导得到 LG 公司反应函数（如图 2）：
Q2＝（90－Q1）/2
（2）
图1
图2
该曲线也是一条斜率为负的曲线，即 LG 公 司 的 利 润 最 大 化 产 量
也是随着 Samsung 公司产量 的 增
定的。 将双方的反应函数移入同一坐标系，曲线的交叉点即为双方产
量的均衡点。 在图中以 E 点表示（如图 3）。 达到均衡时，双方厂家都在
对方一定产量的前提下达到了自身的最佳产量， 即利润最大化产量，
他们 会 将 这 一 产 量 保 持 ，以 维 护 双 方 利 益 。 联 立 方 程 （1）和 （2），得 到
Q1=30，Q2=30，此值即为 Cournot 市场上两个公司的均衡产量。 此时的
总产量为 60，带入市场需求函数，可得到均衡市场价格 40。
2 Stackelberg 模型
Cournot 模型中厂商在进行产量决策时还有这样的假设， 即 两 个
厂商的决策同时进
行。 而在现实中，当企
业产量被看作是企业
加而减少。 这一点充分说明在
Cournot 模 型 对 寡 头 垄 断 市 场 的
分析中， 在市场需求一定的前提
下， 寡头企业们不会随意增大产
量而打压市场价格。 相反他们会
不约而同地在保证合理价格的前
提下进行利润最大化产量决策。
那么在通过猜测对方产量来
追求利润最大化的过程中， 双方
图3
厂商有没有可能同时达到利润最大化产量形成市场均衡呢？ 答案是肯
【关键词】博弈理论；经济学模型；竞争战略；市场均衡 The Analysis and Comparison of Cournot and Stackelberg Models AN Ting
Selfish routing in capacitated networks
Date : June 2003; revised February 2004.
2000 Mathematics Subject Classification. Primary 90C35; 90B10, 90B20, 90C25, 90C27, 91A10, 91A13,
91A43.
Key words and phrases. Selfish Routing, Price of Anarchy, Traffic Assignment, System Optimum, Nash
SELFISH ROUTING IN CAPACITATED NETWORKS
´ R. CORREA, ANDREAS S. SCHULZ, AND NICOLAS ´ E. STIER MOSES JOSE Sloan School of Management and Operations Research Center Massachusetts Institute of Technology 77 Massachusetts Avenue Cambridge, MA 02139-4307
Abstract. According to Wardrop’s first principle, agents in a congested network choose their routes selfishly, a behavior that is captured by the Nash equilibrium of the underlying noncooperative game. A Nash equilibrium does not optimize any global criterion per se, and so there is no apparent reason why it should be close to a solution of minimal total travel time, i.e. the system optimum. In this paper, we offer positive results on the efficiency of Nash equilibria in traffic networks. In contrast to prior work, we present results for networks with capacities and for latency functions that are nonconvex, nondifferentiable, and even discontinuous. The inclusion of upper bounds on arc flows has early been recognized as an important means to provide a more accurate description of traffic flows. In this more general model, multiple Nash equilibria may exist and an arbitrary equilibrium does not need to be nearly efficient. Nonetheless, our main result shows that the best equilibrium is as efficient as in the model without capacities. Moreover, this holds true for broader classes of travel cost functions than considered hitherto.
经济学原理 外部性
免疫注射Immunizations 修复历史性建筑物 Restored historic buildings 研究新技术 Research into new technologies
7
铝市场
The Market for Aluminum...
铝的价格
Price of Aluminum
但是市场失灵依然会发生
But market failures can still happen.
2
市场失灵：外部性
Market Failures: Externalities
当市场结果影响到了除市场中买者和 卖者以外的其他方，产生的副作用就
称为外部性
When a market outcome affects parties other than the buyers and sellers in the market, side-effects created are called externalities.
11
污染与社会最优… Pollution and the Social Optimum…
铝价格
Price of Aluminum
污染成本
Cost of pollution
社会成本
Social cost
供给Supply ( 厂商成本private cost )
最优
Optimum
均衡Equilibrium
需求Demand (private value)
0
Qoptimum QMARKET
铝数量 12
Quantity of Aluminum
生产中的负外部性 Negative Externalities in
【微观经济学】第10章 寡头垄断市场
(differentiated oligopoly) • 勾结行为的(即合作的collusion)独立行动的（即
不合作的）
第二节 古诺（双头）模型
• 数量（产量）竞争(quantity competition)：企 业之间的竞争在于选择不同的产出水平
• 每家公司能够意识到自己的产出决策会影响价格 • 另一个假定为厂商作为一个集团来行动和协调决策，
因此可以获得垄断利润
9
卡特尔模型
• 在这种情况下，卡特尔就像一个多工厂的垄断厂商来行动，选择 产量每个厂商的产量qi来最大化整个行业的利润
• = PQ – [C1(q1) + C2(q2) +…+ Cn(qn)]
因此我们可以得出结论公司1的产量是公司2的两倍，利润也是 公司2的两倍。公司1拥有先发优势。
13第五节 寡头厂商的供来自曲线• 寡头厂商的供给曲线是不存在的。
14
本章概要
• 寡头垄断市场的特征 • 古诺模型 • 斯威齐模型 • 卡特尔模型 • 斯塔克伯格模型
15
本章结束
16
本节内容结束
11
卡特尔模型
• 卡特尔主要存在三个问题 • 这些垄断决策是非法的 • 要求卡特尔的领导者知道市场的需求函数和每家公司的边际成本 • 卡特尔可能是不稳定的 • 每家公司都有动力去增加自己的产量
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先发优势——斯塔克伯格模型
是一个公司在另一个公司之前设定产量的寡头垄断模型。
假定公司1首先设定产量，然后公司2再根据公司1的产量决定 产量。因此，在设定产量时公司1必须考虑公司2如何反应。
的结论可知这两家厂商的均衡产量是（ ）。
实验经济学精品课件 (4)
Search Dynamics in Consumer Choice under Time Pressure: An Eye-Tracking Study (pp. 900-926) Coordination in the Presence of Asset Markets (pp. 927-47)
John A. List
The Persistence of Treatment Effects with Norm-Based Policy Instruments: Evidence from a Randomized Environmental Policy Experiment (pp. 318-22)
作为一门成熟学科的标志2：实验经济学的学术共同体
o 学术团体:ESA——using controlled experiments to learn about economic behavior （1986 Vernon Smith） o 实验经济学期刊：Experimental Economics （1998） o 学术会议：
o 经济学实验室
作为一门成熟学科的标志3：实验研究在顶级期刊的发表数 （以AER2011年5期期刊为例）
o o Vol. 101, No. 1, February 2011 Is Tiger Woods Loss Averse? Persistent Bias in the Face of Experience, Competition, and High Stakes (pp. 129-57)
微观经济学最高限价(一)
微观经济学
第四章 政府管制与市场反击
二、资源浪费
搜索时间增加 讣告：向亡灵寻求线索？
微观经济学
第四章 政府管制与市场反击
三、低质量的非效率
短期：降低房屋的品质 长期：不修建新的出租房 管制害死猫？微观经济学Fra bibliotek微观经济学
第四章 政府管制与市场反击
一、消费者之间配置的非效率
有效率：真正想租到房子的人如愿以偿；租房意 愿不强烈的人租不到房子。 现实：公寓并没有到评价最高的人手上。
微观经济学
第四章 政府管制与市场反击
一、消费者之间配置的非效率
公寓的错误配置是一种“错失的成本”。 解决方法之一：允许转租。 在租金管制下：非法。
最高限价与非效率
“有效率”就是指没有人可以在不损害他人福利 的情况下来改善自己的福利。
在无干预下，市场一般处于有效率状态。
微观经济学
第四章 政府管制与市场反击
最高限价与非效率
如果可以重新安排生产或消费就可以在不损失他 人福利的情况下使一部分人福利改善的话，一个 市场或一个经济体就是非效率的。 案例：房屋租金最高限价。
第四章 政府管制与市场反击
三、最高限价（一）
微观经济学
第四章 政府管制与市场反击
比战争更能摧毁一座城市 的是租金管制。
未名氏
第四章 政府管制与市场反击
通往地狱之路是由良 好愿望铺成的。
哈耶克
1974年 诺贝尔经济学奖
第四章 政府管制与市场反击
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微观经济学
第四章 政府管制与市场反击
经济学 名词解释 英文
1.Demand curve and supply curve and interrelatedconcepts just like elasticity of demand and supply. Demand curve:In economics, the demand curve is the graph depicting the relationship between the price of a certain commodity, and the amount of it that consumers are willing and able to purchase at that given price.Supply curve: A graph showing the hypothetical supply of a product or service that would be available at different price points.Elasticity is the ratio of the percent change in one variable to the percent change in another variable. It is a tool for measuring the responsiveness of a function to changes in parameters in a unitless way. Frequently used elasticities include price elasticity of demand, price elasticity of supply,需求弹性Price elasticity of demand : PED is a measure of responsiveness of the quantity of a good or service demanded to changes in its price. The formula for the coefficient of price elasticity of demand for a good is: The above formula usually yields a negative value, due to the inverse nature of the relationship between price and quantity demanded, For example, if the price increases by 5% and quantity demanded decreases by 5%, then the elasticity at the initial price and quantity = −5%/5% = −1.2. Theory of utility consumer theory1) Utility is a measure of relative satisfaction.2) Law of diminishing marginal utilityThe marginal utility of each (homogenous) unit decreases as the supply of units increases3) Consumer’s surplus: Consumer surplus is the difference between the maximum price a consumer is willing to pay and the actual price they do pay4) The producer surplus is the amount that producers benefit by selling at a market price mechanism that is higher than the least that they would be willing to sell for.5) Attitude people towards risks: risk avoidance, risk preference, risk neutral6) An Engel curve describes how household expenditure on a particular good or service varies with household income.3. Production theory1) The target of a firm pursues the maximum of profitIn economics, returns to scale and economies of scale are related terms that describe what happens as the scale of production increases in the long run.The term returns to scale arises in the context of a firm's production function. It refers to changes in output resulting from a proportional change in all inputs. If output increases by that same proportional change then there are constant returns to scale (CRS). If output increases by less than that proportional change, there are decreasing returns to scale (DRS). If output increases by more than that proportional change, there are increasing returns to scale (IRS). Thus the returns to scale faced by a firm are purely technologically imposed and are not influenced by economic decisions or by market conditions.Economies of scale:is a long run concept and refers to reductions in unit cost as the size of a facility and the usage levels of other inputs increase.The common sources of economies of scale are purchasing (bulk buying of materials through long-term contracts), managerial (increasing the specialization of managers), and technological (taking advantage of returns to scale in the production function). Each of these factors reduces the long run average costs (LRAC) of production Economies of scale refer to a firm's costs; returns to scale describe the relationship between inputs and outputs in a long-run production.Cost theory:1) Opportunity cost:It is kind of sacrifice related to the other best choice available to people who had several mutually exclusive choices.Economic profit: A firm is said to be making an economic profit when its average total cost is less than the price of each additional product at the profit-maximizing output. The economic profit is equal to the quantity output multiplied by the difference between the average total cost and the price.Normal profit = cost: A firm is said to be making a normal profit when its economic profit equals zero.Perfect competitive market; monopolistic competition market; monopolistic market; oligopolistic market. Price discrimination：When sales of identical goods or services are transacted at different prices from the same provider. Price discrimination can only be a feature of monopolistic and oligopolistic markets,Market failure: a concept within economic theory that the allocation of goods and services by a free market is not efficient. Market failures are often associated with information asymmetries, Monopolies, externalities, or public goods. The existence of a market failure is often used as a justification for government intervention in a particular market. However, some types of government policy interventions, such as taxes, subsidies, wage and price controls, and regulations, including attempts to correct market failure, may also lead to an inefficientallocation of resources, (sometimes called government failures). Thus, there is sometimes a choice that whether uses government intervention when market failures occur. Externalities: The actions of agents can have externalities, which are innate to the methods of production. For example, if a firm is producing steel, it pollutes the atmosphere when it makes steel, however, and if it is not forced to pay for the use of this resource, then this cost will be borne not by the firm but by society.Common examples of an externality is environmental harm such as pollution or overexploitation of natural resources. Monopolies:Agents in a market can gain market power, allowing them to block other mutually beneficial gains from trades from occurring. In a monopoly, the market equilibrium will no longer be Pareto optimal. The monopoly will use its market power to restrict output below the quantity at which the marginal social benefit is equal to the marginal social cost of the last unit produced, so as to keep prices and profits high.Information asymmetry deals with the study of decisions in transactions where one party has more or better information than the other. This creates an imbalance of power in transactions which can sometimes cause the transactions to go awry. Examples of this problem are adverse selection and moral hazard.Public good is a good that is non-rival and non-excludable. Non-rivalry means that consumption of the good by one individual does not reduce availability of the good for consumption by others; and non-excludability that no one can be effectively excluded from using the good. Consumers can take advantage of public goods without contributing sufficiently to their creation. This is called the free rider problem. If too many consumers decide to 'free-ride', private costs exceed private benefits and the incentive to provide the good or service through the market disappears. The market thus fails to provide a good or service for which there is a need.Pareto efficiency, or Pareto optimality:Given an initial allocation of goods among a set of individuals, a change to a different allocation that makes at least one individual better off without making any other individual worse off is called a Pareto improvement. An allocation is defined as "Pareto efficient" or "Pareto optimal" when no further Pareto improvements can be made.Rent-seeking generally implies the extraction of uncompensated value from others without making any contribution to productivity, such as by gaining control of land and other pre-existing natural resources, or by imposing burdensome regulations or other government decisions that may affect consumers or businesses. Rent-seeking agents will spend money in socially unproductive ways, such as political lobbying, in order to attain, maintain or increase monopoly power.Monetary policyCentral banks chosen a country's monetary policy and manages a state's currency, money supply, and interest rates in order to reduce unemployment, make Price stability; Economic growth and Financial market stability Interest rate interventionsA central bank controls certain types of short-term interest rates. Lowering the interest is to encourage economic growth and is often used to alleviate times of low economic growth. On the other hand, raising the interest rate is often used in times of high economic growth as a contra-cyclical device to keep the economy from overheating and avoid market bubbles.1.倾销：倾销是指一产品从一国出口到另一国的出口价格低于在正常贸易过程中出口国供消费的同类产品的可比价格，即以低于正常价值的价格进入另一国的商业。